The aim of the study is to construct two vectors for efficient expression of soluble recombinant proteins. The first vector was constructed by cloning the HisSUMO fragment into an expression vector pET30a(+) to fuse with the gene of interest (designated as HisSUMO Express). The second vector was constructed in the same way, but with a hydroxylamine cleavage site between HisSUMO and the gene of interest for an economic purpose (designated as HisSUMO Economic). The mouse fibroblast growth factor-21(mFGF-21), which was difficult to express in routine-used expression vectors, was taken as an example to test the vectors. The results showed that the mFGF-21 was expressed at high level in both vectors. The Sumo/mFGF-21 fusion protein accounted for more than 40% of the total bacterial protein. The fusion protein was purified with Ni-TNA column, and the HisSUMO was removed by cleavage of the fusion protein with either hydroxylamine solution or SUMO protease I. The concentration of the purified mFGF-21 mature protein was 54 mg/L and the recovery rate was 6%. The purified proteins derived from either hydroxylamine or SUMO protease I cleavage could stimulate glucose up-take by adipocytes. These results indicated that both HisSUMO Express and HisSUMO Economic were useful expression vectors for efficient expression of soluble recombinant proteins.
Animals ; Fibroblast Growth Factors ; biosynthesis ; genetics ; Genetic Vectors ; genetics ; Hydroxylamine ; chemistry ; Mice ; Peptide Hydrolases ; chemistry ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Solubility

Cohort study is one of the important research methods in analytical epidemiology because of its clear time sequence relationship, which is better than other observational studies in demonstrating causal association. However, screening diagnosis or other methods are often used to exclude the individuals with outcome events during the enrollment process of the subjects in cohort studies. The accuracy of screening diagnosis and the effectiveness of exclusion will affect the accuracy of the baseline status assessment of the subjects included in the study, which may lead to the causal time sequence reversal of exposure-outcome in the estimation of causal effect. Landmark analysis can be used to control reverse causality by excluding subjects with potentially unknown expose-outcome timing. In this paper, we describe the basic principles and analytical steps of landmark analysis, and use data from the Chinese Longitudinal Healthy Longevity Survey to explore the relationship between physical activity and frailty, and introduce the specific application of landmark analysis for the purpose of facilitating its application and inferring causal effects more accurately in cohort studies.

With completing a baseline survey of a large natural population cohort, conducting regular follow-up has become a key factor in further improving the quality of cohort construction and ensuring its sustainable development. Typical cohort follow-up methods include repeat surveys, routine monitoring, and community-oriented surveillance. However, in practical applications, there are often issues such as high costs, difficulty, and high error rates. Telephone follow-up is an important supplementary method to the methods mentioned above, as it has the characteristics of low cost, fast response, and high quality. However, the with difficult organization, quality control is challenging, response rates are low, and management levels vary widely, which limits its widespread use in large-scale population cohort studies. Given the above problems, this study draws on customer relationship management based on the actual needs of the China Northwest Cohort follow-up. It relies on the REDCap electronic data collection platform to build a telephone follow-up management and quality control system. Targeted solutions are provided for key issues in telephone follow-up implementation, including organizational structure, project management, data collection, and process quality control, to improve the quality control level of telephone follow-up comprehensively and thereby enhance the quality and efficiency of follow-up. We hope to provide standardized follow-up programs and efficient quality control tools for newly established and existing cohort studies.

Objective:To explore the disturbance of metal element balance in mice after exposure to radon.Methods:Mice were randomly divided into control group, radon exposure of 30 WLM group, 60 WLM group and 120 WLM groups, with 10 mice in each group. After radon exposure with the cumulative dose, the lung function of mice was detected by a non-invasive pulmonary function testing instrument. Mice blood was taken from eyeballs. The lungs, heart, liver, kidney and spleen were also collected. HE staining was used to observe the pathological changes of lung tissue. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the content of metal elements, including essential trace elements in the body: chromium (Cr), molybdenum (Mo), cobalt (Co), selenium (Se), copper (Cu), zinc (Zn), manganese (Mn), nickel (Ni), and potentially toxic elements: arsenic (As), tin (Sn), lead (Pb), aluminum (Al), mercury (Hg), cadmium (Cd), and silver (Ag).Results:Compared with the control group, lung ventilation function of the radon-exposed mice was decreased, alveolar structure was destroyed, and the contents of pulmonary metal elements Cr, Al, Pb, Sn( F=0.34, 0.66, 3.14, 1.16, P<0.05) and essential trace elements Mn, Cr, Zn, and Mo in the blood were decreased( F=0.65, 1.44, 0.97, 2.08, P<0.05), while the elements of Cu, Mo, Se and As in the lungs were increased( F=1.31, 1.26, 0.81, 2.04, P<0.05), and the element contents in other tissues also fluctuated. Conclusions:Inhalation of a certain cumulative dose of radon can reduce the lung ventilation function of mice and induce lung inflammation, as well reduce the content of essential trace elements in the lung and blood so that the content of metal elements in the body fluctuates.

Pulmonary fibrosis(PF)is a progressive,interstitial fibrotic lung disease characterized by persistent scar formation in the lung parenchyma,and a reduced quality of life and poor prognosis for patients.The pathogenesis of PF is unknown and there is a lack of effective therapeutic agents;however,animal models are currently the main tool used to explore the pathogenesis of the disease and to find effective therapeutic agents.PF can be induced by various factors and to different degrees according to known etiologies.Among these,bleomycin-induced models are widely used because of their reproducibility and the similarity between the fibrosis pathology and clinical conditions.The main induction method include intratracheal drip,intratracheal nebulization,tail vein injection,intraperitoneal injection,and transnasal inhalation,and these can be classified into single and multiple doses,according to the frequency of induction.Based on the relevant literature,the current review summarizes the characteristics of the bleomycin-induced PF model using different induction frequencies and method,to provide a basis for the application of this model.

Objective To compare the success rate and stability of rat pulmonary fibrosis(PF)models induced by intratracheal instillation of different doses of bleomycin(BLM).Methods One hundred and fifty Sprague Dawley rats were divided randomly into control,low-dose BLM 3 mg/kg(BL-L),and high-dose BLM 5 mg/kg(BL-H)groups.General status,mortality,and weight changes were observed,and the lung inspiratory capacity(IC),vital capacity(VC),chord compliance(Cchord),and dynamic compliance(Cdyn)were detected on days 28,42,56,and 84.Lung coefficients were recorded and pathological changes in lung tissue were observed by hematoxylin and eosin and Masson staining.The lung hydroxyproline(HYP)content was detected and collagen type Ⅲ(COL Ⅲ)was detected by immunohistochemistry.Results The mortality rates in the BL-L and BL-H groups were 20％and 28％,respectively.Body weight was significantly lower in the BL-L group compared with the control group on days 0～56,and weight recovery after day 56.Body weight was significantly lower in the BL-H group compared with the control and BL-L groups from days 0～56(P＜0.01).Regarding lung function,IC,VC,Cchord,and Cdyn were significantly lower in the BL-L group compared with the control group on day 28(P＜0.01,P＜0.05),and IC and Cdyn were significantly lower in the BL-H group(P＜0.01).IC,VC,and Cchord were significantly decreased in the BL-L group on day 42(P＜0.01,P＜0.05),while IC,VC,Cchord,and Cdyn were significantly decreased in the BL-H group(P＜0.01,P＜0.05),and IC,VC,and Cchord were significantly lower compared with in the BL-L group(P＜0.01).Cchord was significantly lower in the BL-H group compared with the control and BL-L groups on day 56(P＜0.01).The lung coefficients on day 28 were significantly higher in the BL-L and BL-H groups compared with the control group(P＜0.01),and were significantly higher in the BL-H group from days 42～56 compared with the BL-L and control groups(P＜0.01).Regarding lung histopathology and immunohistochemistry,inflammatory infiltration,fibrotic streaks,and COL Ⅲ expression were observed in the BL-L group from days 28～56,and almost complete disappearance of the fibrotic lesions on day 84.In contrast,fibrotic lesions could be observed from days 28～84 in the BL-H group,with significantly elevated COL Ⅲ expression compared with the control group(P＜0.01).The HYP content was significantly higher in the BL-L group compared with the control group from days 28～42(P＜0.05,P＜0.01),and then gradually decreased,and the HYP content was significantly higher in the BL-H group than in the control group from days 28～84(P＜0.01).Conclusions Both 3 and 5 mg/kg BLM can successfully induce PF rat models.Rats treated with 3 mg/kg BLM developed fibrosis on day 28,which lasted until day 42 and then gradually recovered.Rats treated with 5 mg/kg BLM developed fibrosis on day 28,and the degree of fibrosis was more severe with the higher compared with the lower dose,with stable fibrotic lesions up to day 56 and moderate-to-severe fibrosis still present in half of the rats until day 84.